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Kraemer S, Schneider DJ, Paterson C, Perry D, Westacott MJ, Hagar Y, Katilius E, Lynch S, Russell TM, Johnson T, Astling DP, DeLisle RK, Cleveland J, Gold L, Drolet DW, Janjic N. Crossing the Halfway Point: Aptamer-Based, Highly Multiplexed Assay for the Assessment of the Proteome. J Proteome Res 2024. [PMID: 39038188 DOI: 10.1021/acs.jproteome.4c00411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Measuring responses in the proteome to various perturbations improves our understanding of biological systems. The value of information gained from such studies is directly proportional to the number of proteins measured. To overcome technical challenges associated with highly multiplexed measurements, we developed an affinity reagent-based method that uses aptamers with protein-like side chains along with an assay that takes advantage of their unique properties. As hybrid affinity reagents, modified aptamers are fully comparable to antibodies in terms of binding characteristics toward proteins, including epitope size, shape complementarity, affinity and specificity. Our assay combines these intrinsic binding properties with serial kinetic proofreading steps to allow highly effective partitioning of stable specific complexes from unstable nonspecific complexes. The use of these orthogonal methods to enhance specificity effectively overcomes the severe limitation to multiplexing inherent to the use of sandwich-based methods. Our assay currently measures half of the unique proteins encoded in the human genome with femtomolar sensitivity, broad dynamic range and exceptionally high reproducibility. Using machine learning to identify patterns of change, we have developed tests based on measurement of multiple proteins predictive of current health states and future disease risk to guide a holistic approach to precision medicine.
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Affiliation(s)
- Stephan Kraemer
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Daniel J Schneider
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Clare Paterson
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Darryl Perry
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Matthew J Westacott
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Yolanda Hagar
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Evaldas Katilius
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Sean Lynch
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Theresa M Russell
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Ted Johnson
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - David P Astling
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Robert Kirk DeLisle
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Jason Cleveland
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Larry Gold
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Daniel W Drolet
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
| | - Nebojsa Janjic
- SomaLogic, 2495 Wilderness Place, Boulder, Colorado 80301, United States of America
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Li D, Su Y, Li J, Liu R, Fang B, He J, Xu W, Zhu L. Applications and Challenges of Bacteriostatic Aptamers in the Treatment of Common Pathogenic Bacteria Infections. Biomacromolecules 2023; 24:4568-4586. [PMID: 37728999 DOI: 10.1021/acs.biomac.3c00634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
The continuous evolution and spread of common pathogenic bacteria is a major challenge in diagnosis and treatment with current biotechnology and modern molecular medicine. To confront this challenge, scientists urgently need to find alternatives for traditional antimicrobial agents. Various bacteriostatic aptamers obtained through SELEX screening are one of the most promising strategies. These bacteriostatic aptamers can reduce bacterial infection by blocking bacterial toxin infiltration, inhibiting biofilm formation, preventing bacterial invasion of immune cells, interfering with essential biochemical processes, and other mechanisms. In addition, aptamers may also help enhance the function of other antibacterial materials/drugs when used in combination. This paper has reviewed the bacteriostatic aptamers in the treatment of common pathogenic bacteria infections. For this aspect, first, bacteriostatic aptamers and their screening strategies are summarized. Then, the effect of molecular tailoring and modification on the performance of the bacteriostatic aptamer is analyzed, and the antibacterial mechanism and antibacterial strategy based on aptamers are introduced. Finally, the key technical challenges and their development prospects in clinical treatment are also carefully discussed.
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Affiliation(s)
- Diandian Li
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Yuan Su
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Jie Li
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Rong Liu
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Bing Fang
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Jingjing He
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Wentao Xu
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
| | - Longjiao Zhu
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100193, China
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Ochoa S, Milam VT. Modified Nucleic Acids: Expanding the Capabilities of Functional Oligonucleotides. Molecules 2020; 25:E4659. [PMID: 33066073 PMCID: PMC7587394 DOI: 10.3390/molecules25204659] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 12/20/2022] Open
Abstract
In the last three decades, oligonucleotides have been extensively investigated as probes, molecular ligands and even catalysts within therapeutic and diagnostic applications. The narrow chemical repertoire of natural nucleic acids, however, imposes restrictions on the functional scope of oligonucleotides. Initial efforts to overcome this deficiency in chemical diversity included conservative modifications to the sugar-phosphate backbone or the pendant base groups and resulted in enhanced in vivo performance. More importantly, later work involving other modifications led to the realization of new functional characteristics beyond initial intended therapeutic and diagnostic prospects. These results have inspired the exploration of increasingly exotic chemistries highly divergent from the canonical nucleic acid chemical structure that possess unnatural physiochemical properties. In this review, the authors highlight recent developments in modified oligonucleotides and the thrust towards designing novel nucleic acid-based ligands and catalysts with specifically engineered functions inaccessible to natural oligonucleotides.
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Affiliation(s)
- Steven Ochoa
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA;
| | - Valeria T. Milam
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA;
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
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Percze K, Mészáros T. Analysis of Modified Nucleotide Aptamer Library Generated by Thermophilic DNA Polymerases. Chembiochem 2020; 21:2939-2944. [PMID: 32490558 PMCID: PMC7689754 DOI: 10.1002/cbic.202000236] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/27/2020] [Indexed: 01/31/2023]
Abstract
One of the pivotal steps in aptamer selection is the amplification of target‐specific oligonucleotides by thermophilic DNA polymerases; it can be a challenging task if nucleic acids possessing modified nucleotides are to be amplified. Hence, the identification of compatible DNA polymerase and modified nucleotide pairs is necessary for effective selection of aptamers with unnatural nucleotides. We present an in‐depth study of using 5‐indolyl‐AA‐dUTP (TAdUTP) to generate oligonucleotide libraries for aptamer selection. We found that, among the eight studied DNA polymerases, only Vent(exo‐) and KOD XL are capable of adapting TAdUTP, and that replacing dTTP did not have a significant effect on the productivity of KOD XL. We demonstrated that water‐in‐oil emulsion PCR is suitable for the generation of aptamer libraries of modified nucleotides. Finally, high‐throughput sequence analysis showed that neither the error rate nor the PCR bias was significantly affected by using TAdUTP. In summary, we propose that KOD XL and TAdUTP could be effectively used for aptamer selection without distorting the sequence space of random oligonucleotide libraries.
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Affiliation(s)
- Krisztina Percze
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, 1094, Budapest, Tűzoltó u. 37-47, Ungarn
| | - Tamás Mészáros
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, 1094, Budapest, Tűzoltó u. 37-47, Ungarn
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Abstract
The modern version of the RNA World Hypothesis begins with activated ribonucleotides condensing (nonenzymatically) to make RNA molecules, some of which possess (perhaps slight) catalytic activity. We propose that noncanonical ribonucleotides, which would have been inevitable under prebiotic conditions, might decrease the RNA length required to have useful catalytic function by allowing short RNAs to possess a more versatile collection of folded motifs. We argue that modified versions of the standard bases, some with features that resemble cofactors, could have facilitated that first moment in which early RNA molecules with catalytic capability began their evolutionary path toward self-replication.
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Ren X, Gelinas AD, von Carlowitz I, Janjic N, Pyle AM. Structural basis for IL-1α recognition by a modified DNA aptamer that specifically inhibits IL-1α signaling. Nat Commun 2017; 8:810. [PMID: 28993621 PMCID: PMC5634487 DOI: 10.1038/s41467-017-00864-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 08/01/2017] [Indexed: 01/07/2023] Open
Abstract
IL-1α is an essential cytokine that contributes to inflammatory responses and is implicated in various forms of pathogenesis and cancer. Here we report a naphthyl modified DNA aptamer that specifically binds IL-1α and inhibits its signaling pathway. By solving the crystal structure of the IL-1α/aptamer, we provide a high-resolution structure of this critical cytokine and we reveal its functional interaction interface with high-affinity ligands. The non-helical aptamer, which represents a highly compact nucleic acid structure, contains a wealth of new conformational features, including an unknown form of G-quadruplex. The IL-1α/aptamer interface is composed of unusual polar and hydrophobic elements, along with an elaborate hydrogen bonding network that is mediated by sodium ion. IL-1α uses the same interface to interact with both the aptamer and its cognate receptor IL-1RI, thereby suggesting a novel route to immunomodulatory therapeutics. The cytokine interleukin 1α (IL-1α) plays an important role in inflammatory processes. Here the authors use SELEX to generate a modified DNA aptamer which specifically binds IL-1α, present the structure of the IL-1α/aptamer complex and show that this aptamer inhibits the IL-1α signaling pathway.
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Affiliation(s)
- Xiaoming Ren
- Department of Molecular, Cellular, and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA.,Department of Chemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT, 06511, USA
| | - Amy D Gelinas
- SomaLogic, Inc., 2945 Wilderness Place, Boulder, CO, 80301, USA
| | | | - Nebojsa Janjic
- SomaLogic, Inc., 2945 Wilderness Place, Boulder, CO, 80301, USA
| | - Anna Marie Pyle
- Department of Molecular, Cellular, and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT, 06511, USA. .,Department of Chemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT, 06511, USA.
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7
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Idili A, Ricci F, Vallée-Bélisle A. Determining the folding and binding free energy of DNA-based nanodevices and nanoswitches using urea titration curves. Nucleic Acids Res 2017; 45:7571-7580. [PMID: 28605461 PMCID: PMC5737623 DOI: 10.1093/nar/gkx498] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/23/2017] [Accepted: 05/27/2017] [Indexed: 11/13/2022] Open
Abstract
DNA nanotechnology takes advantage of the predictability of DNA interactions to build complex DNA-based functional nanoscale structures. However, when DNA functional and responsive units that are based on non-canonical DNA interactions are employed it becomes quite challenging to predict, understand and control their thermodynamics. In response to this limitation, here we demonstrate the use of isothermal urea titration experiments to estimate the free energy involved in a set of DNA-based systems ranging from unimolecular DNA-based nanoswitches to more complex DNA folds (e.g. aptamers) and nanodevices. We propose here a set of fitting equations that allow to analyze the urea titration curves of these DNA responsive units based on Watson-Crick and non-canonical interactions (stem-loop, G-quadruplex, triplex structures) and to correctly estimate their relative folding and binding free energy values under different experimental conditions. The results described herein will pave the way toward the use of urea titration experiments in the field of DNA nanotechnology to achieve easier and more reliable thermodynamic characterization of DNA-based functional responsive units. More generally, our results will be of general utility to characterize other complex supramolecular systems based on different biopolymers.
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Affiliation(s)
- Andrea Idili
- Chemistry Department, University of Rome Tor Vergata, Rome 00133, Italy
| | - Francesco Ricci
- Chemistry Department, University of Rome Tor Vergata, Rome 00133, Italy
| | - Alexis Vallée-Bélisle
- Laboratory of Biosensors and Nanomachines, Département de Chimie, Université de Montréal, Montreal, Québec H3T-1J4, Canada
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Wang X, Hoshika S, Peterson RJ, Kim MJ, Benner SA, Kahn JD. Biophysics of Artificially Expanded Genetic Information Systems. Thermodynamics of DNA Duplexes Containing Matches and Mismatches Involving 2-Amino-3-nitropyridin-6-one (Z) and Imidazo[1,2-a]-1,3,5-triazin-4(8H)one (P). ACS Synth Biol 2017; 6:782-792. [PMID: 28094993 DOI: 10.1021/acssynbio.6b00224] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Synthetic nucleobases presenting non-Watson-Crick arrangements of hydrogen bond donor and acceptor groups can form additional nucleotide pairs that stabilize duplex DNA independent of the standard A:T and G:C pairs. The pair between 2-amino-3-nitropyridin-6-one 2'-deoxyriboside (presenting a {donor-donor-acceptor} hydrogen bonding pattern on the Watson-Crick face of the small component, trivially designated Z) and imidazo[1,2-a]-1,3,5-triazin-4(8H)one 2'-deoxyriboside (presenting an {acceptor-acceptor-donor} hydrogen bonding pattern on the large component, trivially designated P) is one of these extra pairs for which a substantial amount of molecular biology has been developed. Here, we report the results of UV absorbance melting measurements and determine the energetics of binding of DNA strands containing Z and P to give short duplexes containing Z:P pairs as well as various mismatches comprising Z and P. All measurements were done at 1 M NaCl in buffer (10 mM Na cacodylate, 0.5 mM EDTA, pH 7.0). Thermodynamic parameters (ΔH°, ΔS°, and ΔG°37) for oligonucleotide hybridization were extracted. Consistent with the Watson-Crick model that considers both geometric and hydrogen bonding complementarity, the Z:P pair was found to contribute more to duplex stability than any mismatches involving either nonstandard nucleotide. Further, the Z:P pair is more stable than a C:G pair. The Z:G pair was found to be the most stable mismatch, forming either a deprotonated mismatched pair or a wobble base pair analogous to the stable T:G mismatch. The C:P pair is less stable, perhaps analogous to the wobble pair observed for C:O6-methyl-G, in which the pyrimidine is displaced into the minor groove. The Z:A and T:P mismatches are much less stable. Parameters for predicting the thermodynamics of oligonucleotides containing Z and P bases are provided. This represents the first case where this has been done for a synthetic genetic system.
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Affiliation(s)
- Xiaoyu Wang
- Department
of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Shuichi Hoshika
- Foundation for Applied Molecular Evolution, 13709 Progress Boulevard, No. 7, Alachua, Florida 32615, United States
| | - Raymond J. Peterson
- Celadon Laboratories, 6525 Belcrest
Road, Hyattsville, Maryland 20782, United States
| | - Myong-Jung Kim
- Foundation for Applied Molecular Evolution, 13709 Progress Boulevard, No. 7, Alachua, Florida 32615, United States
| | - Steven A. Benner
- Foundation for Applied Molecular Evolution, 13709 Progress Boulevard, No. 7, Alachua, Florida 32615, United States
- Firebird Biomolecular Sciences LLC, 13709 Progress Boulevard, No. 17, Alachua, Florida 32615, United States
| | - Jason D. Kahn
- Department
of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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Pfeiffer F, Rosenthal M, Siegl J, Ewers J, Mayer G. Customised nucleic acid libraries for enhanced aptamer selection and performance. Curr Opin Biotechnol 2017; 48:111-118. [PMID: 28437710 DOI: 10.1016/j.copbio.2017.03.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 03/28/2017] [Accepted: 03/30/2017] [Indexed: 12/24/2022]
Abstract
Aptamers are short single-stranded oligo(deoxy)nucleotides that are selected to bind to target molecules with high affinity and specificity. Because of their sophisticated characteristics and versatile applicability, aptamers are thought to become universal molecular probes in biotechnological and therapeutic applications. However, the variety of possible interactions with a putative target molecule is limited by the chemical repertoire of the natural nucleobases. Consequently, many desired targets are not addressable by aptamers. This obstacle is overcome by broadening the chemical diversity of aptamers, mainly achieved by nucleobase-modifications and the introduction of novel bases or base pairs. We discuss these achievements and the characteristics of the respective modified aptamers, reflected by SOMAmers (slow off-rate modified aptamers), clickmers, and aptamers bearing an expanded genetic alphabet.
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Affiliation(s)
- Franziska Pfeiffer
- Life and Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
| | - Malte Rosenthal
- Life and Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
| | - Julia Siegl
- Life and Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
| | - Jörg Ewers
- Life and Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
| | - Günter Mayer
- Life and Medical Sciences Institute, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany; Center of Aptamer Research and Development, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany.
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Minagawa H, Onodera K, Fujita H, Sakamoto T, Akitomi J, Kaneko N, Shiratori I, Kuwahara M, Horii K, Waga I. Selection, Characterization and Application of Artificial DNA Aptamer Containing Appended Bases with Sub-nanomolar Affinity for a Salivary Biomarker. Sci Rep 2017; 7:42716. [PMID: 28256555 PMCID: PMC5335659 DOI: 10.1038/srep42716] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/12/2017] [Indexed: 12/21/2022] Open
Abstract
We have attained a chemically modified DNA aptamer against salivary α-amylase (sAA), which attracts researchers’ attention as a useful biomarker for assessing human psychobiological and social behavioural processes, although high affinity aptamers have not been isolated from a random natural DNA library to date. For the selection, we used the base-appended base (BAB) modification, that is, a modified-base DNA library containing (E)-5-(2-(N-(2-(N6-adeninyl)ethyl))carbamylvinyl)-uracil in place of thymine. After eight rounds of selection, a 75 mer aptamer, AMYm1, which binds to sAA with extremely high affinity (Kd < 1 nM), was isolated. Furthermore, we have successfully determined the 36-mer minimum fragment, AMYm1-3, which retains target binding activity comparable to the full-length AMYm1, by surface plasmon resonance assays. Nuclear magnetic resonance spectral analysis indicated that the minimum fragment forms a specific stable conformation, whereas the predicted secondary structures were suggested to be disordered forms. Thus, DNA libraries with BAB-modifications can achieve more diverse conformations for fitness to various targets compared with natural DNA libraries, which is an important advantage for aptamer development. Furthermore, using AMYm1, a capillary gel electrophoresis assay and lateral flow assay with human saliva were conducted, and its feasibility was demonstrated.
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Affiliation(s)
- Hirotaka Minagawa
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Kentaro Onodera
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Hiroto Fujita
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Taiichi Sakamoto
- Department of Life and Environmental Sciences, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino 275-0016, Japan
| | - Joe Akitomi
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Naoto Kaneko
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Ikuo Shiratori
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Masayasu Kuwahara
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Katsunori Horii
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
| | - Iwao Waga
- Innovation Laboratory, NEC Solution Innovators, Ltd., 1-18-7, Shinkiba, Koto-Ku, Tokyo 136-8627, Japan
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